Within seconds of tasting the drink Sunday afternoon, authorities said 67-year-old Jan Harding's mouth and throat started to burn.

An analysis of the drink by police found there wasn't only tea in the serving container -- there was a mix of cleaning chemicals as well.

"I don't know how much was put into this drink, but from what I understand, it was a highly toxic substance and the amount in there caused some severe burns to her mouth and her throat," South Jordan Officer Sam Winkler said.

Inside Harding's glass was a mixture of tea and what authorities said the restaurant uses to clean the fryers.

It's a cleaning blend made up of 67 percent sodium hydroxide, a chemical that can be deadly when ingested.

"It can cause pretty severe burns, potentially burn through the esophagus and cause some severe bleeding and internal injuries," Dr. Spencer Smith said, who works in the emergency room at the University of Utah Hospital.

FOX 13 News reached out to the franchise owner, Finger Lickin Brands LLC., which runs the South Jordan Dickey's as well as others.

In a statement, company President John Thomson said: "Our thoughts and prayers go out to our guest and her family. Safety is something we take very seriously when it comes to our valued guests, as well as our own team members. At this time we are fully involved in cooperating with all parties. Out of respect for the privacy of our guest and her family, we will reserve further remarks for the time being."

Harding, a Sandy resident, was rushed to a nearby hospital and later taken by medical helicopter to the University of Utah Hospital's burn center, where she is in critical condition.

"Is this something that was stored improperly? Was it an accident? Was it intentional? We really don't know," Winkler said. "That's why our investigators are looking in on this case."

Following Sunday's incident, the Salt Lake County Health Department was called to the restaurant to inspect the facility.

Officials found there was no existing risk to the public after completing a routine review.